Background: Little is known about co-medical illnesses in black and white patients with probable Alzheimer's disease (AD).
Methods: To address this question, we used two methods. In the first (Group I), black and white probable AD patients were matched on age at presentation to the clinic, age of onset of AD, duration of illness, and Mini-Mental State Examination scores; then, a variety of co-medical illnesses were compared between blacks and whites. In Group II, whites were randomly matched to blacks on the variables listed above.
Results: In Group I, blacks were found to have a higher rate of hypertension than whites, whereas whites had a higher incidence of atrial fibrillation and cancer than blacks. In Group II, age at presentation to the clinic was found to be shorter for men than for women; duration of illness was shorter for black men than for white men, white women, and black women; and Mini-Mental State Examination scores were lower in blacks than whites. As in Group I, blacks were found to have a higher rate of hypertension, whereas whites had higher rates of atrial fibrillation, cancer, coronary artery disease, high cholesterol, and gastrointestinal disease.
Conclusion: In both groups, black patients with probable AD had a higher rate of hypertension than white patients with probable AD, and whites had higher rates of atrial fibrillation and cancer. This finding suggests that these comorbid illnesses in black and white patients with probable AD is not due to a statistical Type II error, but rather to differences in these groups.